ESTIMATED ERROR IN USING NATIONAL INCIDENCE FIGURES VS. STATE ESTIMATES FOR RARE DISEASE CALCULATIONS OF ESTIMATED CASES AND COST PER CASE DETECTED IN NEWBORN SCREENING (NBS)- CONGENITAL ADRENAL HYPERPLASIA (CAH) AND CONGENITAL HYPOTHYROIDI ...
Author(s)
Alotaibi A, Rittenhouse B
MCPHS University, Boston, MA, USA
OBJECTIVES: In 2006, the American College of Medical Genetics (ACMG) recommended a significantly expanded group of rare conditions for state-based US NBS programs. Initial efforts to explore the implications of this expansion used national incidence data applied to the states due to an inability to gather current state-specific numbers. Older state-specific numbers were later identified. This research assesses the error associated with estimating consequences of these programs by using national vs. state-specific incidence estimates. METHODS: We collected data on national disease incidence and state-specific numbers of births (2011), state-specific disease cases (2003 and 2006) and number of required NBS tests/birth and reported fees. We developed two estimates of cases: 1) expected cases by applying national incidence to current state births and 2) cases identified using state-specific actual observations (averaged over the 2 years and applied to current number of births). We also calculated the cost per expected identified case using both methods of estimating cases. RESULTS: The differences in numbers based on state actuals vs. expected cases calculated from national incidence estimates was expressed as a percentage of the actuals. For CH this ranged from -71% to + 200% (mean=-33%; 46 were negative; 2 were positive; 3 unchanged) and in CAH from -67% to + 500% (mean=+70%; 9 were negative; 22 were positive; 7 unchanged and 13 missing or undefined due to no cases being in the denominator of the calculation). Similar differences were observed in calculations of cost per identified cases. CONCLUSIONS: Sampling variation and the association with ethnicity and other differences by state demographics implied added variation in state actuals compared to national incidence used in predictions. The one-sided error observed in the CH calculations leads us to question the accuracy of the national incidence figure. Application of national incidence to state-specific situations should proceed with caution.
Conference/Value in Health Info
2014-05, ISPOR 2014, Palais des Congres de Montreal
Value in Health, Vol. 17, No. 3 (May 2014)
Code
PSY70
Topic
Economic Evaluation
Topic Subcategory
Cost/Cost of Illness/Resource Use Studies
Disease
Rare and Orphan Diseases